 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.texteditor.quickdiff;

 import java.util.List ;
 import java.util.ListIterator ;

 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.source.Annotation;
 import org.eclipse.jface.text.source.ILineDiffInfo;

 import org.eclipse.ui.internal.texteditor.NLSUtility;
 import org.eclipse.ui.internal.texteditor.quickdiff.compare.rangedifferencer.RangeDifference;


 /**
  * The local implementation of <code>ILineDiffInfo</code>. As instances are
  * also <code>Annotation</code>s, they can be used in
  * <code>DocumentLineDiffer</code>s <code>IAnnotationModel</code> protocol.
  *
  * @since 3.0
  */
 public final class DiffRegion extends Annotation implements ILineDiffInfo {
     private final RangeDifference fDifference;

     private final int fOffset;

     private final List fList;

     private final IDocument fDocument;

     /**
      * Creates a new diff region.
      *
      * @param difference
      * @param offset
      * @param differences
      * @param source
      */
     public DiffRegion(RangeDifference difference, int offset, List differences, IDocument source) {
         super("org.eclipse.ui.workbench.texteditor.quickdiffChange", false, null); //$NON-NLS-1$
 fOffset= offset;
         fDifference= difference;
         fList= differences;
         fDocument= source;
     }

     /*
      * @see org.eclipse.jface.text.source.Annotation#getType()
      */
     public String getType() {
         // we return unknown for unchanged regions to avoid
 // them getting displayed.
 switch (getChangeType()) {
             case CHANGED:
                 return "org.eclipse.ui.workbench.texteditor.quickdiffChange"; //$NON-NLS-1$
 case ADDED:
                 return "org.eclipse.ui.workbench.texteditor.quickdiffAddition"; //$NON-NLS-1$
 case UNCHANGED:
                 return "org.eclipse.ui.workbench.texteditor.quickdiffUnchanged"; //$NON-NLS-1$
 default:
                 return TYPE_UNKNOWN;
         }
     }

     /*
      * @see org.eclipse.jface.text.source.ILineDiffInfo#getRemovedLinesBelow()
      */
     public int getRemovedLinesBelow() {
         if (fOffset == fDifference.rightLength() - 1) {

             if (getChangeType() != UNCHANGED)
                 return Math.max(fDifference.leftLength() - fDifference.rightLength(), 0);

             synchronized (fList) {
                 for (ListIterator it= fList.listIterator(); it.hasNext();) {
                     if (fDifference.equals(it.next())) {
                         if (it.hasNext()) {
                             RangeDifference next= (RangeDifference) it.next();
                             if (next.rightLength() == 0)
                                 return Math.max(next.leftLength() - next.rightLength(), 0);
                         }
                         break;
                     }
                 }
             }
         }
         return 0;
     }

     /*
      * @see org.eclipse.jface.text.source.ILineDiffInfo#getChangeType()
      */
     public int getChangeType() {
         if (fDifference.kind() == RangeDifference.NOCHANGE)
             return UNCHANGED;
         if (fOffset >= fDifference.leftLength())
             return ADDED;
         return CHANGED;
     }

     /*
      * @see org.eclipse.jface.text.source.ILineDiffInfo#getRemovedLinesAbove()
      */
     public int getRemovedLinesAbove() {
         if (getChangeType() == UNCHANGED && fOffset == 0) {
             synchronized (fList) {
                 for (ListIterator it= fList.listIterator(fList.size()); it.hasPrevious();) {
                     if (fDifference.equals(it.previous())) {
                         if (it.hasPrevious()) {
                             RangeDifference previous= (RangeDifference) it.previous();
                             return Math.max(previous.leftLength() - previous.rightLength(), 0);
                         }
                         break;
                     }
                 }
             }
         }
         return 0;
     }

     /*
      * @see org.eclipse.jface.text.source.ILineDiffInfo#hasChanges()
      */
     public boolean hasChanges() {
         return getChangeType() != UNCHANGED || getRemovedLinesAbove() > 0 || getRemovedLinesBelow() > 0;
     }

     /*
      * @see org.eclipse.jface.text.source.ILineDiffInfo#getOriginalText()
      */
     public String [] getOriginalText() {
         IDocument doc= fDocument;
         if (doc != null) {
             int startLine= fDifference.leftStart() + fOffset;
             if (startLine >= fDifference.leftEnd())
                 return new String [0]; // original text of an added line is
 // empty

             int endLine= startLine + getRemovedLinesBelow();
             if (getChangeType() == UNCHANGED)
                 startLine++;
             String [] ret= new String [endLine - startLine + 1];
             for (int i= 0; i < ret.length; i++) {
                 try {
                     ret[i]= doc.get(doc.getLineOffset(startLine + i), doc.getLineLength(startLine + i));
                 } catch (BadLocationException e) {
                     ret[i]= ""; //$NON-NLS-1$
 }
             }
             return ret;
         }

         // in initialization phase?
 return new String [0];
     }

     /*
      * @see org.eclipse.jface.text.source.Annotation#getText()
      */
     public String getText() {
         int r= fDifference.rightLength();
         int l= fDifference.leftLength();
         int c= Math.min(r, l);
         int a= r - l;
         String changed= c > 0 ? NLSUtility.format(QuickDiffMessages.quickdiff_annotation_changed, new Integer (c)) : null;
         String added;
         if (a > 0)
             added= NLSUtility.format(QuickDiffMessages.quickdiff_annotation_added, new Integer (a));
         else if (a < 0)
             added= NLSUtility.format(QuickDiffMessages.quickdiff_annotation_deleted, new Integer (-a));
         else
             added= null;
         String line= c > 1 || c == 0 && Math.abs(a) > 1 ? QuickDiffMessages.quickdiff_annotation_line_plural : QuickDiffMessages.quickdiff_annotation_line_singular;

         String ret= (changed != null ? changed : "") + (changed != null ? " " + line : "") //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
 + (changed != null && added != null ? ", " : " ") + (added != null ? added : "") //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$
 + (added != null && changed == null ? " " + line : ""); //$NON-NLS-1$//$NON-NLS-2$
 return ret;
     }

     /**
      * @return Returns the difference.
      */
     public RangeDifference getDifference() {
         return fDifference;
     }

     /**
      * @return Returns the offset.
      */
     public int getOffset() {
         return fOffset;
     }
 }

